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<h2>
Environment Commands</h2>
Environments provide a structure for creating a consistent environment
for processes using one or more of the features of Berkeley DB.&nbsp; Unlike
some of the database commands, the environment commands are very low level.
<br>
<hr WIDTH="100%">
<p>The user may create and open a new DB environment&nbsp; by invoking:
<p><b>> berkdb env</b>
<br><b>&nbsp;&nbsp;&nbsp; [-cdb] [-cdb_alldb] [-lock] [-log] [-txn [nosync]]</b>
<br><b>&nbsp;&nbsp;&nbsp; [-create] [-home<i> directory</i>] [-mode <i>mode</i>]</b>
<br><b>&nbsp;&nbsp;&nbsp; [-data_dir <i>directory</i>] [-log_dir <i>directory</i>]
[-tmp_dir <i>directory</i>]</b>
<br><b>&nbsp;&nbsp;&nbsp; [-nommap] [-private] [-recover] [-recover_fatal]
[-system_mem] [-errfile <i>filename</i>]</b>
<br><b>&nbsp;&nbsp;&nbsp; [-use_environ] [-use_environ_root] [-verbose
{<i>which </i>on|off}]</b>
<br><b>&nbsp;&nbsp;&nbsp; [-region_init]</b>
<br><b>&nbsp;&nbsp;&nbsp; [-cachesize {<i>gbytes bytes ncaches</i>}]</b>
<br><b>&nbsp;&nbsp;&nbsp; [-mmapsize<i> size</i>]</b>
<br><b>&nbsp;&nbsp;&nbsp; [-log_max <i>max</i>]</b>
<br><b>&nbsp;&nbsp;&nbsp; [-log_buffer <i>size</i>]</b>
<br><b>&nbsp;&nbsp;&nbsp; [-lock_conflict {<i>nmodes </i>{<i>matrix</i>}}]</b>
<br><b>&nbsp;&nbsp;&nbsp; [-lock_detect default|oldest|random|youngest]</b>
<br><b>&nbsp;&nbsp;&nbsp; [-lock_max <i>max</i>]</b>
<br><b>&nbsp;&nbsp;&nbsp; [-lock_max_locks <i>max</i>]</b>
<br><b>&nbsp;&nbsp;&nbsp; [-lock_max_lockers <i>max</i>]</b>
<br><b>&nbsp;&nbsp;&nbsp; [-lock_max_objects <i>max</i>]</b>
<br><b>&nbsp;&nbsp;&nbsp; [-lock_timeout <i>timeout</i>]</b>
<br><b>&nbsp;&nbsp;&nbsp; [-overwrite]</b>
<br><b>&nbsp;&nbsp;&nbsp; [-txn_max <i>max</i>]</b>
<br><b>&nbsp;&nbsp;&nbsp; [-txn_timeout <i>timeout</i>]</b>
<br><b>&nbsp;&nbsp;&nbsp; [-client_timeout <i>seconds</i>]</b>
<br><b>&nbsp;&nbsp;&nbsp; [-server_timeout <i>seconds</i>]</b>
<br><b>&nbsp;&nbsp;&nbsp; [-server <i>hostname</i>]</b>
<br><b>&nbsp;&nbsp;&nbsp; [-rep_master] [-rep_client]</b>
<br><b>&nbsp;&nbsp;&nbsp; [-rep_transport <i>{ machineid sendproc }</i>]</b>
<br>&nbsp;
<p>This command opens up an environment.&nbsp;&nbsp; We automatically set
the DB_THREAD and the DB_INIT_MPOOL flags.&nbsp; The arguments are:
<ul>
<li>
<b>-cdb</b> selects the DB_INIT_CDB flag for Concurrent Data Store</li>

<li>
<b>-cdb_alldb</b> selects the DB_CDB_ALLDB flag for Concurrent Data Store</li>

<li>
<b>-lock</b> selects the DB_INIT_LOCK flag for the locking subsystem</li>

<li>
<b>-log</b> selects the DB_INIT_LOG flag for the logging subsystem</li>

<li>
<b>-txn</b> selects the DB_INIT_TXN, DB_INIT_LOCK and DB_INIT_LOG flags
for the transaction subsystem.&nbsp; If <b>nosync</b> is specified, then
it will also select DB_TXN_NOSYNC to indicate no flushes of log on commits</li>

<li>
<b>-create </b>selects the DB_CREATE flag to create underlying files</li>

<li>
<b>-home <i>directory </i></b>selects the home directory of the environment</li>

<li>
<b>-data_dir <i>directory </i></b>selects the data file directory of the
environment by calling <a href="../../docs/api_c/env_set_data_dir.html">DBENV->set_data_dir</a>.</li>

<li>
<b>-log_dir <i>directory </i></b>selects the log file directory of the
environment&nbsp; by calling <a href="../../docs/api_c/env_set_lg_dir.html">DBENV->set_lg_dir</a>.</li>

<li>
<b>-tmp_dir <i>directory </i></b>selects the temporary file directory of
the environment&nbsp; by calling <a href="../../docs/api_c/env_set_tmp_dir.so">DBENV->set_tmp_dir</a>.</li>

<li>
<b>-mode <i>mode </i></b>sets the permissions of created files to <b><i>mode</i></b></li>

<li>
<b>-nommap</b> selects the DB_NOMMAP flag to disallow using mmap'ed files</li>

<li>
<b>-private</b> selects the DB_PRIVATE flag for a private environment</li>

<li>
<b>-recover</b> selects the DB_RECOVER flag for recovery</li>

<li>
<b>-recover_fatal</b> selects the DB_RECOVER_FATAL flag for catastrophic
recovery</li>

<li>
<b>-system_mem</b> selects the DB_SYSTEM_MEM flag to use system memory</li>

<li>
<b>-errfile </b>specifies the error file to use for this environment to
<b><i>filename</i></b>
by calling <a href="../../docs/api_c/env_set_errfile.html">DBENV->set_errfile</a><b><i>.
</i></b>If
the file already exists then we will append to the end of the file</li>

<li>
<b>-use_environ</b> selects the DB_USE_ENVIRON flag to affect file naming</li>

<li>
<b>-use_environ_root</b> selects the DB_USE_ENVIRON_ROOT flag to have the
root environment affect file naming</li>

<li>
<b>-verbose</b> produces verbose error output for the given which subsystem,
using the <a href="../../docs/api_c/dbenv_set_verbose.html">DBENV->set_verbose</a>
method.&nbsp;&nbsp; See the description of <a href="#> <env> verbose which on|off">verbose</a>
below for valid <b><i>which </i></b>values</li>

<li>
<b>-region_init </b>specifies that the user wants to page fault the region
in on startup using the <a href="../../docs/api_c/env_set_region_init.html">DBENV->set_region_init</a>
method call</li>

<li>
<b>-cachesize </b>sets the size of the database cache to the size&nbsp;
specified by <b><i>gbytes </i></b>and <b><i>bytes, </i></b>broken up into
<b><i>ncaches</i></b>
number of caches using the <a href="../../docs/api_c/env_set_cachesize.html">DBENV->set_cachesize</a>
method</li>

<li>
<b>-mmapsize </b>sets the size of the database page to <b><i>size </i></b>using
the <a href="../../docs/api_c/env_set_mp_mmapsize.html">DBENV->set_mp_mmapsize</a>
method</li>

<li>
<b>-log_max </b>sets the maximum size of the log file to <b><i>max</i></b>
using the <a href="../../docs/api_c/env_set_lg_max.html">DBENV->set_lg_max</a>
call</li>

<li>
<b>-log_regionmax </b>sets the size of the log region to <b><i>max</i></b>
using the <a href="../../docs/api_c/env_set_lg_regionmax.html">DBENV->set_lg_regionmax</a>
call</li>

<li>
<b>-log_buffer </b>sets the size of the log file in bytes to <b><i>size</i></b>
using the <a href="../../docs/api_c/env_set_lg_bsize.html">DBENV->set_lg_bsize</a>
call</li>

<li>
<b>-lock_conflict </b>sets the number of lock modes to <b><i>nmodes</i></b>
and sets the locking policy for those modes to the <b><i>conflict_matrix</i></b>
given using the <a href="../../docs/api_c/env_set_lk_conflict.html">DBENV->set_lk_conflict</a>
method call</li>

<li>
<b>-lock_detect </b>sets the deadlock detection policy to the given policy
using the <a href="../../docs/env_set_lk_detect.html">DBENV->set_lk_detect</a>
method call.&nbsp; The policy choices are:</li>

<ul>
<li>
<b>default</b> selects the DB_LOCK_DEFAULT policy for default detection</li>

<li>
<b>oldest </b>selects DB_LOCK_OLDEST to abort the oldest locker on a deadlock</li>

<li>
<b>random</b> selects DB_LOCK_RANDOM to abort a random locker on a deadlock</li>

<li>
<b>youngest</b> selects DB_LOCK_YOUNGEST to abort the youngest locker on
a deadlock</li>
</ul>

<li>
<b>-lock_max_locks </b>sets the maximum number of locks to <b><i>max </i></b>using
the <a href="../../docs/api_c/env_set_lk_max_locks.html">DBENV->set_lk_max_locks</a>
method call</li>

<li>
<b>-lock_max_lockers </b>sets the maximum number of locking entities to
<b><i>max
</i></b>using the <a href="../../docs/api_c/env_set_lk_max_lockers.html">DBENV->set_lk_max_lockers</a>
method call</li>

<li>
<b>-lock_max_objects </b>sets the maximum number of simultaneously locked
objects to <b><i>max </i></b>using the <a href="../../docs/api_c/env_set_lk_max_objects.html">DBENV->set_lk_max_objects</a>
method call</li>

<li>
<b>-lock_timeout </b>sets the timeout for locks in the environment</li>

<li>
<b>-overwrite </b>sets DB_OVERWRITE flag</li>

<li>
<b>-txn_max </b>sets the maximum size of the transaction table to <b><i>max</i></b>
using the <a href="../../docs/api_c/env_set_txn_max.html">DBENV->set_txn_max</a>
method call</li>

<li>
<b>-txn_timeout </b>sets the timeout for transactions in the environment</li>

<li>
<b>-client_timeout</b> sets the timeout value for the client waiting for
a reply from the server for RPC operations to <b><i>seconds</i></b>.</li>

<li>
<b>-server_timeout</b> sets the timeout value for the server to determine
an idle client is gone to <b><i>seconds</i></b>.</li>

<li>
<b>-server </b>specifies the <b><i>hostname</i></b> of the server
to connect to in the <a href="../../docs/api_c/env_set_server.html">DBENV->set_server</a>
call.</li>

<li>
<b>-rep_client </b>sets the newly created environment to be a
replication client, using the <a href="../../docs/api_c/rep_client.html">
DBENV->rep_client</a> call.</li>

<li>
<b>-rep_master </b>sets the newly created environment to be a
replication master, using the <a href="../../docs/api_c/rep_master.html">
DBENV->rep_master</a> call.</li>

<li>
<b>-rep_transport </b>specifies the replication transport function,
using the
<a href="../../docs/api_c/rep_transport.html">DBENV->rep_set_transport</a>
call.  This site's machine ID is set to <b><i>machineid</i></b> and
the send function, a Tcl proc, is set to <b><i>sendproc</i></b>.</li>

</ul>

This command will invoke the <a href="../../docs/api_c/env_create.html">db_env_create</a>
function.&nbsp; After it successfully gets a handle to an environment,
we bind it to a new Tcl command of the form <b><i>envX</i></b>, where X
is an integer starting at&nbsp; 0 (e.g. <b>env0, env1, </b>etc).&nbsp;
We use the <i>Tcl_CreateObjCommand()</i> to create the top level environment
command function.&nbsp; It is through this handle that the user can access
all the commands described in the <a href="#Environment Commands">Environment
Commands</a> section.&nbsp; Internally, the handle we get back from DB
will be stored as the <i>ClientData</i> portion of the new command set
so that all future environment calls will have that handle readily available.&nbsp;
Then we call the <a href="../../docs/api_c/env_open.html">DBENV->open</a>
method call and possibly some number of setup calls as described above.
<p>
<hr WIDTH="100%">
<br><a NAME="> <env> verbose which on|off"></a><b>> &lt;env> verbose <i>which</i>
on|off</b>
<p>This command controls the use of debugging output for the environment.&nbsp;
This command directly translates to a call to the <a href="../../docs/api_c/dbenv_set_verbose.html">DBENV->set_verbose</a>
method call.&nbsp; It returns either a 0 (for success), a DB error message
or it throws a Tcl error with a system message.&nbsp; The user specifies
<b><i>which</i></b>
subsystem to control, and indicates whether debug messages should be turned
<b>on</b>
or <b>off</b> for that subsystem.&nbsp; The value of <b><i>which</i></b>
must be one of the following:
<ul>
<li>
<b>deadlock </b>- Chooses the deadlocking code by using the DB_VERB_DEADLOCK
value</li>

<li>
<b>recovery </b>- Chooses the recovery code by using the DB_VERB_RECOVERY
value</li>

<li>
<b>wait </b>- Chooses the waitsfor code by using the DB_VERB_WAITSFOR value</li>
</ul>

<hr WIDTH="100%">
<p><a NAME="> <env> close"></a><b>> &lt;env> close</b>
<p>This command closes an environment and deletes the handle.&nbsp; This
command directly translates to a call to the <a href="../../docs/api_c/env_close.html">DBENV->close</a>
method call.&nbsp; It returns either a 0 (for success), a DB error message
or it throws a Tcl error with a system message.
<p>Additionally, since the handle is no longer valid, we will call <i>Tcl_DeleteCommand()
</i>so
that further uses of the handle will be dealt with properly by Tcl itself.
<p>Also, the close command will automatically abort any <a href="txn.html">transactions</a>
and close any <a href="mpool.html">mpool</a> memory files.&nbsp; As such
we must maintain a list of open transaction and mpool handles so that we
can call <i>Tcl_DeleteCommand</i> on those as well.
<p>
<hr WIDTH="100%">

<b>> berkdb envremove<br>
[-data_dir <i>directory</i>]<br>
[-force]<br>
[-home <i>directory</i>]<br>
[-log_dir <i>directory</i>]<br>
[-overwrite]<br>
[-tmp_dir <i>directory</i>]<br>
[-use_environ]<br>
[-use_environ_root]</b>

<p>This command removes the environment if it is not in use and deletes
the handle.&nbsp; This command directly translates to a call to the <a href="../../docs/api_c/env_remove.html">DBENV->remove</a>
method call.&nbsp; It returns either a 0 (for success), a DB error message
or it throws a Tcl error with a system message.&nbsp; The arguments are:
<ul>
<li>
<b>-force</b> selects the DB_FORCE flag to remove even if other processes
have the environment open</li>

<li>
<b>-home <i>directory</i> </b>specifies the home directory of the environment</li>

<li>
<b>-data_dir <i>directory </i></b>selects the data file directory of the
environment by calling <a href="../../docs/api_c/env_set_data_dir.html">DBENV->set_data_dir</a>.</li>

<li>
<b>-log_dir <i>directory </i></b>selects the log file directory of the
environment&nbsp; by calling <a href="../../docs/api_c/env_set_lg_dir.html">DBENV->set_lg_dir</a>.</li>

<li>
<b>-overwrite </b>sets DB_OVERWRITE flag</li>

<li>
<b>-tmp_dir <i>directory </i></b>selects the temporary file directory of
the environment&nbsp; by calling <a href="../../docs/api_c/env_set_tmp_dir.so">DBENV->set_tmp_dir</a>.</li>

<li>
<b>-use_environ </b>selects the DB_USE_ENVIRON flag to affect file naming</li>

<li>
<b>-use_environ_root</b> selects the DB_USE_ENVIRON_ROOT flag to affect
file naming</li>
</ul>

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